Fire TV Stick 1 Rooting, Recovery, and ROM Guide: Unrootable

The Fire TV Stick 1 running software versions 54.1.2.3 and older cannot be rooted. However, there is a chance that the device will update to a rootable software version if you allow it to update once. You should let it update and then immediately disconnect its WiFi access so that it does not install additional updates. If you’re lucky it will update to a rootable software version before updating to the latest software version, which is probably unrootable.